On the topic of changing insurance:
Doesn't this now appear in the Schufa?
To my knowledge, providers can reject you later (after cancellation and switching). Then you are practically listed on a blacklist and no one wants you as a customer.
Strange from my point of view is that natural hazard damages are unlimited, but damages from precipitation are only insured up to 2000 EUR.
Wherever the boundary might be drawn.
The former is the natural force itself, the second largest is the damages that result only from the consequences. Creeping rainwater over a period is therefore not a natural hazard damage, but merely rainwater that later causes damage.